1. Field of the Invention
The invention relates to a control apparatus for a vehicle including a continuously variable transmission mechanism and a gear mechanism provided in parallel with each other between an engine and a drive wheel.
2. Description of Related Art
There is well known a power transmission system including a continuously variable transmission mechanism and a gear mechanism provided in parallel with each other between an input rotating member and an output rotating member. The gear mechanism has a gear stage. The power of an engine is transmitted to the input rotating member. The output rotating member outputs the power to a drive wheel. This is, for example, a power transmission system for a vehicle, described in International Application Publication No. 2013/176208. International Application Publication No. 2013/176208 describes the power transmission system for a vehicle, including a power transmission path through a belt-type continuously variable transmission and a power transmission path through a gear train. The power transmission paths are provided in parallel with each other between an input shaft and an output shaft. A first clutch and a dog clutch are provided in the power transmission path through the gear train. The first clutch transmits or interrupts power. A second clutch is provided in the power transmission path through the continuously variable transmission. The second clutch transmits or interrupts power. In this power transmission system for a vehicle, the speed ratio of the power transmission path through the gear train is set so as to be lower than the lowest vehicle speed-side speed ratio (maximum speed ratio) that can be established by the power transmission path through the continuously variable transmission. Thus, when the vehicle starts moving, the first clutch is engaged, and the power of the engine is transmitted by the power transmission path through the gear train, with the result that the vehicle is driven.
Incidentally, there may be a deviation between a command hydraulic pressure and an actual hydraulic pressure in hydraulic control over the first clutch or there may be a case where the first clutch does not operate as intended in response to an actual hydraulic pressure. In such a case, for example, at a designed command hydraulic pressure (designed hydraulic pressure) at which the first clutch should become a pressure regulating state, there is a possibility that the first clutch does not actually become the pressure regulating state. If it happens, in control that uses the first clutch (for example, in garage control for engaging the first clutch as a result of changing a shift lever from N position to D position or in returning from neutral control for slipping or releasing the first clutch during a stop of the vehicle), there is a concern that an engagement shock of the first clutch occurs or increases. The above-described inconvenience is not publicly known. The pressure regulating state is a state where it is possible to control a clutch torque (torque capacity) in response to a supplied hydraulic pressure from the timing (touch point) at which the piston of a clutch begins to contact a friction plate (clutch plate).